Atomic orbital-wise characterization of the vibronic attractive interaction in a model of an oxygen-containing organic polymer

Abstract

The extended local vibronic constant (ELVC) is introduced for the study of the strength of local electron pairing for superconductivity based on vibronic interaction using a model of an oxygen-containing organic polymer. The ELVC consists of the electrostatic part and the two-electron part, which originates in the response of the electron density to the nuclear vibration. It is found that the two-electron part has opposite sign to, and almost the same magnitude as, that of the electrostatic part. The difference between the ELVC and the Fock matrix derivative, which is related to the derivative of the Hückel parameters used as the electron–phonon coupling constant, is discussed. The vibronic interaction in the in-plane orbitals, which is characteristic of the interaction in a two-dimensional conductor, is also discussed. Keywords: vibronic interaction, superconductivity, local electron pairing, extended local vibronic constant, abinitio calculation.